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Title: Ultrafast dynamics of neutral, ultracold plasmas

Abstract

The ultrafast dynamics of a neutral, ultracold plasma following an energy landscape shift is studied theoretically and with simulation. To lowest order in time, the inertial dynamics on the new landscape can be characterized by the initial-state plasma microfield, which, for the randomly ordered case of an ultracold neutral plasma, is dominated by nearest-neighbor interactions. Formation of the pair correlation function arises after ballistic overshoot, which leads to oscillations in the effective temperature. Connections are made to similar properties of clusters, photoisomerization of molecules, and nonthermal melting in solids.

Authors:
 [1]
  1. Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Publication Date:
OSTI Identifier:
20975025
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2436853; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COLD PLASMA; CORRELATION FUNCTIONS; ELECTRON TEMPERATURE; INTERACTIONS; ION TEMPERATURE; MOLECULES; OSCILLATIONS; PLASMA WAVES; SIMULATION

Citation Formats

Murillo, Michael S. Ultrafast dynamics of neutral, ultracold plasmas. United States: N. p., 2007. Web. doi:10.1063/1.2436853.
Murillo, Michael S. Ultrafast dynamics of neutral, ultracold plasmas. United States. doi:10.1063/1.2436853.
Murillo, Michael S. Tue . "Ultrafast dynamics of neutral, ultracold plasmas". United States. doi:10.1063/1.2436853.
@article{osti_20975025,
title = {Ultrafast dynamics of neutral, ultracold plasmas},
author = {Murillo, Michael S.},
abstractNote = {The ultrafast dynamics of a neutral, ultracold plasma following an energy landscape shift is studied theoretically and with simulation. To lowest order in time, the inertial dynamics on the new landscape can be characterized by the initial-state plasma microfield, which, for the randomly ordered case of an ultracold neutral plasma, is dominated by nearest-neighbor interactions. Formation of the pair correlation function arises after ballistic overshoot, which leads to oscillations in the effective temperature. Connections are made to similar properties of clusters, photoisomerization of molecules, and nonthermal melting in solids.},
doi = {10.1063/1.2436853},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
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  • We describe the optical diagnostics used to study ultracold neutral plasmas. Imaging and spectroscopy based on both ion absorption and fluorescence provide accurate measurements of ion kinetic energy, plasma size, and the number of ions in the plasma. Absorption measurements yield lower signal-to-noise ratios because they are highly sensitive to laser intensity fluctuations, but the resulting measurement of the number of ions requires no external calibration. Fluorescence measurements of ion number must be calibrated with absorption measurements, but the measurements are less sensitive to technical noise sources. Spatially resolved fluorescence measurements also have the advantage of separating ion kinetic energymore » due to expansion from thermal kinetic energy.« less
  • We present the first measurements and simulations of recombination fluorescence from ultracold neutral calcium plasmas. This method probes three-body recombination at times less than 1 {mu}s, shorter than previously published time scales. For the lowest initial electron temperatures, the recombination rate scales with the density as n{sub 0}{sup 2.2}, significantly slower than the predicted n{sub 0}{sup 3}. Recombination fluorescence opens a new diagnostic window in ultracold plasmas. In most cases it probes deeply bound level populations that depend critically on electron energetics. However, a perturbation in the calcium 4snd Rydberg series allows our fluorescence measurements to probe the population inmore » weakly bound levels that result just after recombination.« less